title: Tributyltin (TBT) and mitochondrial respiration in mussel digestive gland.
abstract: The toxicity of organotins and especially tri-n-butyltin (TBT) on mitochondria is well known. However as far as we are aware, effects on mitochondrial respiration are unexplored in mollusks. In this work mitochondria isolated from the digestive gland of Mytilus galloprovincialis and susceptive to the classical respiratory chain inhibitors, were assayed in the presence of micromolar TBT concentrations to investigate mitochondrial respiratory activities. Intact and freeze-thawed mitochondria were used. TBT significantly inhibited oxygen consumption in the presence of glutamate/malate or succinate as substrates. Conversely cytochrome c oxidase activity (complex IV), assayed both polarographically and spectrophotometrically, was unaffected. The addition of 1,4-dithioerythritol (DTE) decreased the TBT-driven inhibition of complexes I and III. The TBT capability of covalent binding to thiol groups of mitochondrial proteins in a dose-dependent manner was confirmed by the aid of Ellman's reagent. Data strongly suggests that TBT may prevent the electron transfer from complexes I and III to downhill respiratory chain complexes by binding to critical SH residues.
authors.affiliation: Department of Biochemistry G. Moruzzi, University of Bologna, Via Tolara di Sopra, 50, 40064 Ozzano Emilia (BO), Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Nesci
authors.forename: Vittoria
authors.initials: V
authors.lastname: Ventrella
authors.forename: Fabiana
authors.initials: F
authors.lastname: Trombetti
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pirini
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pagliarani
mesh_terms: D000818:Animals; D019069:Cell Respiration / Q000187:drug effects; D004064:Digestive System / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004579:Electron Transport / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D049878:Mytilus / Q000187:drug effects* / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D014220:Trialkyltin Compounds / Q000008:administration & dosage / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D014220:Trialkyltin Compounds; D014874:Water Pollutants, Chemical; C011559:tributyltin; D003576:Electron Transport Complex IV